IIM Calcutta - Indian Institute of Management

Hello Dadu Dayal, It's very nice to hear from you that you have already started thinking of doing your MBA from IIM Kolkata. To have such precise and clear-cut aim is indeed a great trait of a student. Once you have decided on your aim, you can definitely work towards achieving it. You have got reasonably good marks in 10th, 12th and engineering so what is left now is to crack CAT with good marks. Hence I would advise you to study well, take tuition, online coaching and then only appear for this common admission test for IIMs. I am sure once you do this you will get admission in your dream institute.
Best wishes to you.

The sale of application forms has already begun. The date for sale and receipt of application form is 12th May 2019. The entrance examination for advertising and PR will be on 26th May 2019.

Hello! There are a total of 454 students pursuing MBA at IIM Kolkata. https://www.iimcal.ac.in/programs/pgp/placements/job-placements
Here is the source link.

Hello! Well, nothing can be said with complete surety but a score of at least 99 percentile should be sufficient to get an interview call from some (if not all) of the B-schools mentioned above. Good luck!

I hope this link will help you https://www.shiksha.com/college/indian-institute-of-mass-communication/iimc-entrance-exam

Yes, graduation percentage are negotiable.
Good luck.